A.\(6\).
B.\(8\).
C.\(4\).
D.\(2\).

A.\(V = \dfrac{{\pi \left( {{{\rm{e}}^2} - 1} \right)}}{2}\)
B.\(\dfrac{{\pi {{\rm{e}}^2}}}{2}\).
C.\(V = \dfrac{{{{\rm{e}}^2} - 1}}{2}\)
D.\(V = \dfrac{{\pi \left( {{{\rm{e}}^2} + 1} \right)}}{2}\).

A.\(( - 1;1)\).
B.\((0;2)\)
C.\((0;1)\)
D.\((1;2)\)

A.\(a < 0,b < 0,c < 0\).
B.(a > 0,b < 0,c < 0\).
C.\(a > 0,b > 0,c < 0\)
D.\(a > 0,b < 0,c > 0\).

A.\(\dfrac{{\sqrt 3 {a^3}}}{{12}}\).
B.\(\dfrac{{3{a^3}}}{4}\)
C.\(\dfrac{{{a^3}}}{4}\).
D.\(\dfrac{{\sqrt 3 {a^3}}}{4}\).

A.\(4\).
B.\(3\). 
C.\(2\sqrt 2 \).
D.\(2\sqrt 3 \).

A.\(1\).
B.\(0\).
C.\(2\)
D.\(3\).

A.\(S = \left| {\int\limits_a^b {f\left( x \right)} {\rm{ dx}}} \right|\).
B.\(S =  - \int\limits_a^0 {f\left( x \right){\rm{dx}}}  - \int\limits_0^b {f\left( x \right)} {\rm{ dx}}\).
C.\(S = \int\limits_a^0 {f\left( x \right){\rm{dx}}}  + \int\limits_0^b {f\left( x \right)} {\rm{ dx}}\).
D.\(S = \left| {\int\limits_a^0 {f\left( x \right){\rm{dx}}} } \right| + \left| {\int\limits_0^b {f\left( x \right)} {\rm{ dx}}} \right|\).

A.\(2\).
B.Vô số.
C.\(3\).
D.\(4\).

A.\(\dfrac{{2a}}{{\sqrt {13} }}\)
B.\(\dfrac{{2a\sqrt 3 }}{{13}}\)
C.\(\dfrac{{2a\sqrt {39} }}{{13}}\)
D.\(\dfrac{{a\sqrt {39} }}{{13}}\)